<!DOCTYPE html>
<html>
    <head>
        <script src="js/vue.js"></script>
        <style>
            .box {
                background-color: pink;
                width: 100%;
                height: 200px;
            }

            .inner {
                background-color: red;
                width: 100px;
                height: 50px;
                border: 2px solid white;
            }
        </style>
    </head>
    <body>
        <div id="app">
            <div v-bind:class="box1">
                我是box
                <div v-bind:class="inner1">
                    我是inner1
                </div>
                <div v-bind:class="inner1">
                    我是inner2
                </div>
            </div>
        </div>

        <script>
            var vm = new Vue({
                el:'#app',
                data:{
                    box1 : 'box',
                    inner1 : 'inner'
                }
            });
        </script>
    </body>
</html>